Moving Files From One Directory To Another

Which built-in PHP functions would I use to move a file from one directory into another? I'm thinking that this requires more than one function to achieve what I want. What approaches should I take? Do I need to copy the file into a temporary directory first and then move it to the destination directory? Or Is it possible for me to move the file directly from one directory into another? The functions I read about so far are copy() and move_uploaded_file(), but the move_uploaded_file() function seems to work only when the file is uploaded from an HTML form, or am I wrong? Just looking for some direction. - Nilaab